Program.cs

using System;

namespace ReferenceTypes
{
    class Program
    {
        static void Main(string[] args)
        {   //int, decimal, float, enum, boolean = value type
            int number1 = 10;//The value of "number1" is equal to 10 (int: type, number1: alias, 10: value)
            int number2 = 20;//The value of "number2" is equal to 20 (int: type, number1: alias, 20: value)

            number1 = number2;//The value of "number1" is equal to the value of "number2", which is 20.
                              //Meaning: number1 = 20
            number2 = 100;//The value of "number2" is now 100.

            Console.WriteLine("Number 1 = " + number1);
            //               ("Number 1: " + 20);

            // Sequentially
            // "number1" defined as 10 (var "number1" created in stack, its value assigned in stack)
            // "number2" defined as 20 (var "number2" created in stack, its value assigned in stack)
            // "number1" defined as 20 (preceding value assignment of "number1" in stack obsoleted)
            // "number2" defined as 100 (preceding value assignment of "number2" in stack obsoleted)
            // Console.WriteLine("Number 1" + 20) (output current value of "number1", which is now 20)

            //array, class, interface... reference type
            int[] numbers1 = new int[] { 1, 2, 3 };//Var "numbers1" created in stack, "new" created an address in heap and assigned value(s) to this address.
            int[] numbers2 = new int[] { 10, 20, 30 };//Var "numbers2" created in stack, "new" created an address in heap and assigned value(s) to this address.

            numbers1 = numbers2;//The address in heap corresponding to var "numbers1" is now equal to the address of var "numbers2" (which contains '{10, 20, 30}'). Meaning: Var "numbers1" now refers to the address containg values "10, 20, 30" in heap.
            numbers2[0] = 1000;//The value in the address for the 0. item of array "numbers2" is 1000. Meaning: 1000 overwrites 10.

            Console.WriteLine("Numbers1[0] = "+ numbers1[0]);

        }
    }

}